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650 alignment
#1

I am aligning a 650 and have the osc tracking nicely (adjust the trimmer in the can at 1600 and the outboard trimmer under the chassis for 610)

The RF does not track well in my observation. I can peak it at the high end or the low end and seems to be very sensitive. I could "optimize" it ,but it would be a shame to waste the gain for poor but even performance accros the band.

Am I expecting too much or should I look further.

Current conditions:
Total Re-cap
Out of tollerence resistors replaced
Tubes "tested" good
Using a 10' antenna for testing.
Blocks rebuilt

Looking for a clue,

Dave Casazza
Keep em glowin and goin...
#2

Mine act the same way, Philco or not. Connect up a 40' long wire, and it's hard to notice or gone all together. This is due to a more favorable L/C ratio in the tuning circuits on higher freqs. If everything aligned up as it should, try a longer antenna. I really doubt you have an issue.

-Brian
If you collect or are interested in antique telephones, please visit Classic Rotary Phones
http://www.classicrotaryphones.com/forum/index.php
#3

I just finished a 650B and found that the rf tracking can be improved on the broadcast band by cheating the dial scale alignment somewhat. With the tuning gang plates fully meshed, try setting the dial scale to the first line to the right of the end of scale line. Now re-align and check your rf tracking. If it is better, but not perfect, move the dial scale a little more in the same direction and try again. I found this procedure helps somewhat.

Ed




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